There are numerous types of plugs available that seal holes. Oftentimes, holes are made in parts for the purposes of connecting other holes together to create internal passageways for fluids. In some cases, holes are made to access internal components that later need to be sealed. A number of solutions are available in multi piece plugs such as ball expansion plugs. These ball expansion plugs involve a cylindrical piece with a cylindrical relief cut out from the inside thereof. A ball is press fit into this cylindrical relief to hold the two together. The assembly is placed in a hole that has a two step diameter such that one end of the cylindrical piece inserts into the hole and stops where the diameter steps down. A hammer, such as a pneumatic hammer is then used to further press the ball into the cylindrical piece and thereby expand the cylindrical piece outwardly to seal the hole. While these are types of plugs work very effectively, they suffer a downside in that two pieces are required to be machined and assembled. This adds expense and complexity. Further, the step down installation hole involves two steps for creation thereof.
Other types of expansion plugs are disclosed in US Pat. Pub. No. 2015/0202754. This type of plug involves a hollow cylinder and an internal tapered piece that is fit to the cylinder. A tool attaches to the internal tapered piece and pulls that piece into the cylinder to expand the cylinder against the hole. This style of plug provides a number of benefits, but is still a two piece plug that may not be suitable for certain applications.
Although simple plugs that do not expand might be capable of being forced into a hole to seal it, the problem is that as such a plug is forced in, it could scratch the sides of the hole and provide a leakage pathway, thus reducing the ability of such a plug to resist elevated pressures.